The use of biometrics to distinguish and differentiate between objects by physical recognition has been in vogue since time immemorial; however the capability for the same was restricted to humans rather than machines.
This had led to limited development of biologically based access control systems as a means of security. The behavioral differentiation in human beings on the other hand had received greater attention thereby measures such as signatures and hand writing patterns were in greater use than physical characteristics.
With the advent of information technology and computers, however greater use of biometrics is feasible particularly in access control systems by using minute human differentiations in physical characteristics such as finger prints, retina of the eye and facial patterns. These differentiations can be exploited to advantage in effective access control based on characteristics of individuals recorded in the system. Since duplication of these is not practicable, it provides virtually fool proof security. (Chirillo. Blaul, 2003).
As technology advances, distinguishing criteria have also increased, thus voice biometrics promises to add a vital second authentication factor to available technologies. (Andersen, 2007). This denotes that use of biometrics for access control is likely to proliferate in the years ahead.
Biometric based access control systems work on the principle of authentication based on biological characteristics of human beings to include the most common one, finger prints, retina of the eye and iris, pattern of the face and now voice. (Andersen, 2007) (Chirillo. Blaul, 2003). Thus biometric technology analyses and measures the biological characteristics of an individual and creates a unique identification for storage and retrieval electronically.
Where behavioral pattern is also required it includes signatures, way of walking, bearing and even pattern of typing. Behaviometrics is a term used in biometrics which indicates analysis based on personal characteristics such as the use of the mouse the pattern which can distinguish one individual from another in remote locations.
Jain (2004) indicates how biometrics uses human physical parameters to advantage. The first and foremost is the principal of universality, in that common physical attributes which are found in every man have to be captured in such systems. This facilitates universal relevance of the system.
The next issue used in biometrics is uniqueness of common characteristics in all persons such as finger prints and iris of the eye which have extremely rare duplication. The characteristics selected also have to be permanent and should be easily measurable each time these are captured for providing access. Moreover these should provide accuracy at continuous regularity and the technology should be easily adaptable to given social and political norms. (Jain, 2004)
Having identified these characteristics, the biometric process works based on information of laid down parameters be it finger prints, retina of the eye or hand configuration within the system. Capturing these details is known as the process of enrollment. During this procedure biometric data base of a persons characteristics are created and stored.
During the next stage information provided by the person is compared with the basic stored information and validated through a sensor. The sensor is essentially an image acquisition system. Having acquired the relevant data of the user, the sensor passes it on to the system which at first rationalizes the data removing clutter and normalizes it for ease of comparison.
Thereafter the features which are required are extracted by providing a vector of numbers or an exact image with all properties in the form of a template. Exact correlation of templates provides authentication every time biometric recognition is required. All these operations are carried out in the least possible time.
The availability of computers and information technology has facilitated this process by enabling storage of large volumes of data, software for comparison and ease of input and output.